Dehydration of emulsions



MayZO, 1947. A. D. SMALL 2,420,687

DEHYDRATION OF EMULSIONS Filed Dec. 21, 1942 Fig.1.

EMULSION INLET Fig 2.

3mm f g I Arf/zun D Smal/ 7/%W ilwm/v Patented May 20, 1947 DEHYDRATIONOF EMULSIONS Arthur D. Small, United States Army, Washington, D.

Application December 21, 1942, Serial N 0. 469,729

1 Claim.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3700. G. 757) The invention described herein ma be manufactured and used byor for the Government for governmental purposes, without payment to meof any royalty thereon.

This application is a continuation-in-part of my copending applicationSerial No. 433,928, filed March 9, 1942, and relates to a process fordehydrating emulsions. More particularly, it relates to a process forseparating the oil and water particles present in the emulsion producedfrom oil reservoirs.

It is an object of this invention to provide a method for rendering suchseparation more expeditious and to provide means whereby the process maybe carried out with a minimum of time and effort.

It is a further object of this invention to provide apparatus forcarrying out the process described which will be of simple constructionand considerably cheaper than present day apparatus, and in whichmaintenance requirements will be a minimum.

These and other objects'and advantages of my invention will becomeapparent upon a consideration of the following detailed description whentaken in conjunction with the accompanying drawing, in which:

Fig. l'is a longitudinal view, partly in cross section, of the separatorand its associated apparatus; and

Fig. 2 is a front view of the separator.

Emulsion produced from oil reservoirs consists of minute globules ofsalt water surrounded by crude oil. It is apparent that, in order todehydrate the emulsion, it is necessary to break or destroy the oilfilms which enclose and separate the small water globules, so that theymay coalesce and form larger globules on which ravity may have a greaterinfluence in bringing about settling, The force which opposes thisagglomeration of water particles can be resolved into terms ofdifferential surface tension and the negative electrical charge of thewater particles.

Instead of depending solely upon such agencies as heat, chemicals, highpotential electrical discharges or the like for such separation, Iemploy mechanical vibrations combined with an electrical discharge. Invibrating the emulsion at a high rate which effects a rapid compressionand decompression'of the fluid, it is believed, in the light of testsmade with the subject apparatus. that, because of the relativeincompressibility of the Water and the compressibility of the crude oil,the vibration breaks the oil film surrounding the water globules,thereby allowing them to unite as larger globules producing a finalseparation of the crude oil and salt water. In order to further expeditethe coalescence of the water globules, an electrical discharge ismaintained at the point of maximum compression of the emulsified fluidto eiTect neutralization of the electrical charge carried by theparticles of the dispersed phase of the emulsion. For carrying out theabove described principles, I have designed the apparatus illustrated.

Referring to the drawing, it will be seen that I have provided arelatively thick brass ring I l as the main body of the separator. Theinside of the ring I! is countersunk on each side in order to take theflange rings 8 and 9 which hold the glass plate I and the steelvibrating plate 6, respectively. in place. The flanges 8 and 9 arefastened to the main brass ring II with screws 5, thereby forming acontainer in which the dehydration of the crude oil takes place. Theemulsiflfid oil is supplied to the center of the container by means ofinlet 1 The separated oil is discharged from the upper outlet 14 and thewater is discharged through an outlet l5 which extends within thecontainer to a position near the bottom thereof, The entire assembly ismounted on suppo ting block :1 which in turn is mounted upon the baseIt.

Referring more particularly to Fig. 1, the following apparatus isprovided to generate the necessary vibration of the steel plate 6. Ascrew 22 is attached to the center of the steel plate 6 and engages onearm of a V-frame l9 movable on the axle 20 which in turn is mounted inpillow block 2!. The other arm of the V-frame l9 carries a small wheel25 arranged to be actuated by the hexagonal cam 26 carried on axle 21mounted on pillow block 3 I. The axle 21, together with the cam 25, isdriven by the motor 28 through pulleys 20 and 30 and the belt 32.

To set up the apparatus for operation, the screw 22 is manipulated sothat the proper clearance exists between the cam wheel 25 and thehexagonal cam 26 and then the lock-nut 23 on the screw 22 is tightenedto maintain the apparatus in the adjusted position. In order to smoothout the operation of the apparatus and to eliminate back lash. a spring24 is connected between the V-frame I 9 and the supporting block l1.With the apparatus so adjusted, rotation of the hexagonal cam 25 willcause an oscillating movement of the V-frame which in turn will vibratethe steel plate 6. I have found that a vibration rate between 10,000 to20,000 cycles per second is most effective in causing the separation ofthe oil and Water particles.

In order to provide for a suitable electrical discharge through theemulsified oil so that the electrical charge of the water particles maybe removed and their coalescence aided, I have provided in the center ofthe glass plate I an electrode l3 having its discharge end l3 situatedimmediately in advance of outlet l2 as clearly shown in Fig. 1 of thedrawings. Electrode I3 is connected to a source of potential which isvariable from approximately 3,000 to 5,000 volts and which will maintaina current flow from 1 to 10 amperes, the particular voltage and currentrequirements being dependent upon the specific gravity of the crude oil.The return Path to the source of potential energy is brought out from asuitable contact on the brass ring I I. Since the electrode [3 does notcome in contact with any metal part of the separator, the currentfollows a path through the emulsion and in so doing removes the negativeelectrical charge which normally exists on the water particles.

Separation of the oil and water being effected as a result of thecombined effect of the mechan ical vibration and the removal of thenegative charge on the water particles as described above, the oil beinglighter than the water will collect in the upper half of the containerand the water will settle to the lower half where they may be readilydrawn off by means of outlets l4 and 15, respectively.

While I have described my invention with particularity, it is to beunderstood that I do not wish to be limited to the particular detailsand arrangements disclosed since various modifications within the spiritof the invention will suggest themselves to one skilled in the art.

Having described my invention, what I claim as new and wish to secure byLetters Patent is:

An apparatus of the continuous flow type for separating the phases of anemulsion comprising a dehydrator including opposed diaphragms spaced todefine a narrow treating chamber, one of said diaphragms being formed ofan insulating material, the other of metal, means for delivering asupply of emulsion to said treating chamber, said means including asupply conduit extending from a source of emulsion supply to theinterior of said chamber and terminating with its outlet orificedisposed between and approximately centrally of said diaphragms, meansattached to the center of said metallic diaphragm for impartingvibratory movement thereto for the purpose of effecting rarefaction andcondensation of the constituent particles of the emulsion, an electrodemounted in said diaphragm of insulating material and provided with adischarge end disposed immediately in advance of said outlet orifice,said discharge end being spaced from the center of said metallicdiaphragm whereby to form an electrical discharge area across the mouthof said outlet orifice, means in electrical relation with said electrodeand said metallic diaphragm for establishing a difference of potentialbetween said electrode discharge end and said metallic diaphragm andacross said discharge area, whereby, as said emulsion emerges from saidoutlet orifice and enters the discharge area extending thereacross, theintensity of the electrical field in said area in connection with thecondensation and rarefaction action of said vibratory diaphragm efiectscoalescence of the water phase of said emulsion into masses which willcollect in the lower portion of said treating chamber beneath the oilphase therein, and means in connection with said dehydrator forseparately removing the oil and water phases of the emulsion as therespective masses thereof collect in the upper and lower portions ofsaid treating chamber whereby to provide an uninterrupted flow throughsaid chamber.

ARTHUR D. SMALL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,828,847 Lawrason Dec. 29, 19311,942,480 Lawrason Jan. 9, 1934 1,591,472 De Brey July 6, 1926 1,394,462Alden et a1 Oct. 18, 1921 2,300,761 Amy Nov. 3, 1942 2,257,997 BarnesOct. 7, 1941 1,781,076 Palmer Nov. 11, 1930 1,430,294 Eddy et a1. Sept.26, 1942 2,138,051 Williams Nov. 29, 1938 2,170,178 Williams Aug. 22,1939 2,083,798 Roberts June 15, 1937 2,033,418 Eddy Mar. 10, 19362,061,197 Kiech Nov. 17, 1936 OTHER REFERENCES Piersol-,ElectricalCondenser Process for Demulsifying OilState of Illinois, Department ofRegistration and Education, Report of Investigations, No. 29, page 16(1933).

